The King and Princess of Wales have stepped out together for the first time in two years, marking a milestone amid the royal family’s continued health issues.

Kate joined the King at the annual Commonwealth Day service in London on Monday, a year after both were forced to cancel because they were receiving cancer treatment.

Last year the service, which honours the 56 independent member countries of the Commonwealth, including Australia, was led by the Queen and the Prince of Wales.

They were there again on Monday, along with Princess Anne and British Prime Minister Sir Keir Starmer for the event at Westminster Abbey to celebrate the Commonwealth’s “powerful influence for good in the world”.

It was the King’s first appearance at the service in two years, while Kate missed it last year during her cancer treatment.

In February last year, Buckingham Palace announced the King had been diagnosed with a form of cancer, while the princess went public with her own diagnosis in a personal video message in March.

She is still making a gradual return to public duties after saying she is in remission.

The King’s own cancer treatment continues.

Earlier, the monarch offered a rather unusual tribute for Commonwealth Day. He became a one-off disc jockey for an online radio show after he was “surprised and delighted” to be asked by Apple Music to showcase 17 of his favourite songs to mark the day.

Among the favourites the King listed was Kylie Minogue’s Locomotion. He said it was “music for dancing” and “has that infectious energy which makes it, I find, incredibly hard to sit still”.

Other song’s on the list were Beyonce’s Crazy In Love – with the King describing her as “exceptional” and congratulating her on her first album of the year Grammy.

There was also Diana Ross’s Upside Down.

“When I was much younger, it was absolutely impossible not to get up and dance when it was played,” the King said.

“I wonder if I can still just manage it.”

He also remembered his grandmother the Queen Mother, playing one of her favourites, Al Bowlly singing The Very Thought of You from the 1930s, and described how music from that period “never fails to lift my spirits”.

Beyonce, who will bring her Cowboy Carter tour to London in June, performed Crazy in Love at the Prince’s Trust Fashion Rocks concert in 2003, the year the single was released.

Other hits were reggae star Bob Marley’s Could You Be Loved, the “superb” Grace Jones’ version of La Vie En Rose, the 1964 hit My Boy Lollipop by Millie Small, Dame Kiri Te Kanawa singing E Te Iwi E (Call to the People), Michael Buble’s Haven’t Met You Yet, Anoushka Shankar playing Indian Summer, the carnival classic Hot Hot Hot by Arrow, and Jools Holland and Ruby Turner with My Country Man.

-with AAP